docs: def srp1(*args,**kargs):
      """Send and receive packets at layer 2 and return only the first answer
  nofilter: put 1 to avoid use of bpf filters
  retry:    if positive, how many times to resend unanswered packets
            if negative, how many times to retry when no more packets are answered
  timeout:  how much time to wait after the last packet has been sent
  verbose:  set verbosity level
  multi:    whether to accept multiple answers for the same stimulus
  filter:   provide a BPF filter
  iface:    work only on the given interface"""
      if not "timeout" in kargs:
          kargs["timeout"] = -1
      a,b=srp(*args,**kargs)
      if len(a) > 0:
          return a[0][1]
      else:
          return None